Medical treatment of a patient often involves intravenous injection or feeding of various solutions into the patient's body. A typical intravenous feeding system comprises a stand for supporting a container filled with an intravenous solution, a tube extending from the container fitted at its end with a needle for insertion into the patient's body, and a valve in or along the tube for regulating the rate of flow of the solution to the patient. Attending medical personnel adjust the valve to regulate the rate of flow of solution into the patient. Valves for this general purpose must regulate the solution flow with great precision, must be capable of effective sterilization, and must be sealed against the entrance of foreign matter into the solution.
Typical valves known in the prior art are shown in U.S. Pat. No. 3,685,787 to Adelberg wherein a wedge type tube squeezer device is disclosed, and in Applicant's U.S. Pat. No. 3,880,401 on which the present application is an improvement. In service such valves have proved to have certain disadvantages. Tube compression or squeezer type devices have the well-known disadvantage of variation of flow rates from set rates resulting from plastic deformation of tubes under compression, thus necessitating successive checking and resetting. They are difficult to use when adjusting the regulated flow, especially one handed, and in some instances it is possible for contamination to be introduced into the solution passing through the valve. Therefore, there has been a need for an improved valve which can be adjusted with one hand and which effectively prevents the entry of contamination into the fluid passing therethrough, while being relatively easy to manufacture and to sterilize.